KR102078266B1 - Porous hydrogel structure for a gas sensor, gas sensor including the same, method of preparing the porous hydrogel structure for the gas sensor - Google Patents

Abstract

Biodegradable polymers; And pH indicator dye; a porous hydrogel structure for a gas sensor, a gas sensor comprising the same, and a method of manufacturing a porous hydrogel structure for the gas sensor is disclosed.

Description

Porous hydrogel structure for a gas sensor, a gas sensor comprising the same, and a method for manufacturing the porous hydrogel structure for the gas sensor {Porous hydrogel structure for a gas sensor, gas sensor including the same, method of preparing the porous hydrogel structure for the gas sensor}

A porous hydrogel structure for a gas sensor, a gas sensor comprising the same, and a method for manufacturing a porous hydrogel structure for the gas sensor.

Recently, as the number of single-parent couples or single-person households increases, interest in freshness of food has increased. As a sensor that confirms the stability of food, a biosensor or a gas sensor is mainly used depending on the object of the substance to be detected and its receptor.

Among them, the gas sensor is used to check the stability of food by detecting gases such as ammonia and hydrogen sulfide or toxic chemicals of food, which are generated when food decays.

In order to confirm food stability for gases such as ammonia and hydrogen sulfide, there is a need for a new gas sensor structure that is easily portable and can easily identify harmful gases present in the food efficiently and quickly.

One aspect is to provide a porous hydrogel structure for a gas sensor that is easy to carry and can efficiently detect harmful gas present in food within a short time.

Another aspect is to provide a gas sensor comprising the porous hydrogel structure.

Another aspect is to provide a method of manufacturing a porous hydrogel structure for a gas sensor capable of mass production at low cost.

According to one aspect,

Biodegradable polymers; And

A porous hydrogel structure for a gas sensor comprising a pH indicator dye is provided.

According to another aspect,

A gas sensor comprising the aforementioned porous hydrogel structure is provided.

According to another aspect,

Mixing a first basic aqueous solution and a biodegradable polymer solution in which a pH indicator dye is dispersed to prepare a first mixed solution having heterogeneous primary phase separation;

Adding a second emulsifier aqueous solution to the first mixed solution to prepare a second mixed solution in which second heterogeneous phase separation is performed;

Removing the solvent from the second mixture to obtain a porous hydrogel structure having pores therein; And

Providing a method of manufacturing a porous hydrogel structure for a gas sensor, including; impregnating the obtained porous hydrogel structure with a second basic solution to prepare a porous hydrogel structure for a gas sensor having pores on its surface; do.

A porous hydrogel structure for a gas sensor according to an aspect includes a biodegradable polymer; And pH indicator dye; containing a porous structure, compared to the non-porous structure has a wide surface area exposed to harmful gases present in the food. Due to this, the porous hydrogel structure for the gas sensor can efficiently detect harmful gases in a short time. In addition, the method of manufacturing a porous hydrogel structure for a gas sensor can be mass-produced at low cost.

1 is a schematic diagram showing a mechanism capable of detecting food decay using a porous hydrogel structure (bead) for a gas sensor according to an embodiment.
Figure 2 is a schematic diagram showing a mechanism capable of detecting food decay using a non-porous hydrogel structure (bead) for a gas sensor according to one embodiment to be compared.
3 is a schematic diagram of a method of manufacturing a porous hydrogel structure (bead) according to one embodiment.
4 is a scanning electron microscope (SEM) photograph of the porous hydrogel beads prepared by Example 1.
5 is a scanning electron microscope (SEM) photograph of the non-porous hydrogel beads prepared by Comparative Example 1.
6 is a water content analysis results for the porous hydrogel beads prepared by Examples 1 to 3.
7 is a photograph showing the color change of the beads after exposure to 0 ppm, 10 ppm, 30 ppm, and 60 ppm of ammonia gas, respectively, for the porous hydrogel beads prepared in Example 3.

Hereinafter, a porous hydrogel structure for a gas sensor according to an exemplary embodiment, a gas sensor including the same, and a method of manufacturing the porous hydrogel structure for a gas sensor will be described in detail with reference to the accompanying drawings. The following are presented as examples, and the present invention is not limited thereby, and the present invention is only defined by the scope of claims to be described later.

In the present specification, "hydrogel structure" means "a structure in which water is introduced into a polymer network structure" and refers to a structure having high permeability and swelling by including an aqueous solution therein.

In the food field, a portable electronic nose has been developed that can detect the amount of volatile organic compounds and detect the freshness and decay of food. The portable electronic nose is portable, but it is premised that equipment for detection and equipment of a smartphone for monitoring must be built.

As an alternative to such a portable electronic nose, a color conversion sensor has been developed that detects a color changing due to interaction with a contained material when sensing a material to be measured. Since the color conversion sensor has a low sensitivity characteristic, a method of promoting a redox reaction of a gas using a redox compound such as ferrocene has been developed to increase the sensitivity characteristic. However, in the case of the redox compound, there is a limitation in that it is used as a food sensor because it has its own harmfulness.

In order to solve this, the inventors of the present invention are to propose a porous hydrogel structure for a gas sensor as follows, a gas sensor including the same, and a method for manufacturing the porous hydrogel structure for the gas sensor.

A porous hydrogel structure for a gas sensor according to an embodiment includes a biodegradable polymer; And pH indicator dyes. The porous hydrogel structure for the gas sensor may include a biodegradable polymer that is harmless to the environment, biocompatible. Since the porous hydrogel structure for the gas sensor is a porous structure, it is not only convenient to carry, but also has a large surface area, so that it can efficiently detect harmful gas present in food in a short time compared to a non-porous structure.

The porous hydrogel structure may further include a water layer on its surface. On the surface of the water film layer of the porous hydrogel structure, harmful gases present in food are dissolved and can be divided into positive and negative ions. Thereafter, cations and anions of the noxious gas are diffused into the structure to react with a pH indicator dye to cause color conversion. As a result, the porous hydrogel structure can detect the presence of the harmful gas.

The porous hydrogel structure may have at least one pore on the inside and the surface of the structure, and the pore size of the surface of the structure may be larger than the pore size inside the structure.

The pores on the surface of the structure may be a result of partially hydrolyzing a biodegradable polymer. Due to this, the specific surface area exposed to the harmful gas present in the food of the structure may be widened. It is possible to more easily and efficiently detect the harmful gas.

The biodegradable polymer may include one or more selected from polyester polymers, anhydrides thereof, and copolymers thereof.

The term "~ polymer" as used herein is used as a concept including "~ polymer" and "~ derivative of polymer".

Examples of the polyester-based polymer include poly (β-hydroxybutyrate), poly (hydroxyvalerate), poly (lactic acid), or poly (glycolic acid). The biodegradable polymer may include anhydrides of the polymers exemplified above and / or copolymers thereof. The biodegradable polymer can be processed into a hydrogel structure, can be freed in a short time, and the decomposition products released in vivo are suitable for low toxicity.

For example, the biodegradable polymer may include a polymer represented by Formula 1 below:

[Formula 1]

In Chemical Formula 1,

R ₁ , R ₂ , R ₃ , R ₄ may be independently a hydrogen atom, a substituted or unsubstituted C1 to C10 alkyl group, or a combination thereof;

m and n may each be an integer of 5 to 100,000.

Looking at the definition of the substitution (group) used in the formula (1) is as follows.

The "substitution" of the alkyl group used in Formula 1 is a halogen atom, an alkyl group of C1 to C10 substituted with a halogen atom (eg CCF ₃ , CHCF ₂ , CH ₂ F, CCl _3, etc.), a hydroxy group, a nitro group, and a cyano group. , Amino group, amidino group, hydrazine, hydrazone, carboxyl group or salt thereof, sulfonic acid group or salt thereof, phosphoric acid or salt thereof, or C1 to C10 alkyl group, C2 to C10 alkenyl group, C2 to C10 alkynyl group, C1 to It means substituted with C10 alkoxy group, C1 to C20 heteroalkyl group, C6 to C20 aryl group, C6 to C20 arylalkyl group, C6 to C20 heteroaryl group, or C6 to C20 heteroarylalkyl group.

Specific examples of the C1 to C10 alkyl group used in Chemical Formula 1 include methyl, ethyl, propyl, isobutyl, sec-butyl, ter-butyl, neo-butyl, iso-amyl, or hexyl, and the alkyl group One or more of the hydrogen atoms may be substituted with a substituent as defined in “Substitution” above.

Specific examples of the C2-C10 alkenyl group used in the "substitution" include vinylene, allylene, and the like.

Specific examples of the C2-C10 alkynyl group used in the "substitution" include acetylene and the like.

Specific examples of the C1 to C10 alkoxy groups used in the "substitution" include methoxy, ethoxy, propoxy, and the like.

The C1 to C20 heteroalkyl group or arylalkyl group used in the "substitution" means that one or more of the carbon atoms constituting the alkyl group is replaced by a hetero group such as N, O, S, or P, or an aryl group such as phenyl. .

The C6 to C20 aryl group used in the "substitution" may be used alone or in combination and means an aromatic system containing one or more rings, and examples thereof include phenyl, naphthyl, tetrahydronaphthyl and the like. . In addition, one or more hydrogen atoms of the aryl group may be substituted with a substituent as defined in “Substitution” described above.

The heteroaryl group of C6 to C20 used in the "substitution" means one or more heteroatoms selected from N, O, P or S, and means that the remaining ring atoms are organic compounds having carbon, for example, pyridyl, etc. Can be lifted.

The heteroaryl alkyl group of C6 to C20 used in the "substitution" means that at least one of the carbon atoms constituting the alkyl group has been replaced with the aforementioned heteroaryl group.

In Chemical Formula 1, R ₁ may be a substituted or unsubstituted C1 to C10 alkyl group, for example, a substituted or unsubstituted C1 to C5 alkyl group, for example, a substituted or unsubstituted C1 to C3 It may be an alkyl group.

The polymer represented by Chemical Formula 1 is a polymer that is harmless to the environment by exhibiting low toxicity as it enters the metabolic pathway (Kreb's cycle) in vivo and can be excreted with carbon dioxide gas and water under the action of an enzyme within a short time.

The pores may have a diameter of 1 μm to 50 μm. The pores, for example, may have a diameter of 5 μm to 50 μm, for example, may have a diameter of 10 μm to 50 μm, for example, may have a diameter of 10 μm to 45 μm, eg For example, it may have a diameter of 10 μm to 40 μm, for example, a diameter of 10 μm to 35 μm.

The porous hydrogel structure may have a porosity of 80% or more. The porous hydrogel structure may have a porosity of 85% or more, for example, a porosity of 87% or more, and a porosity of 88% or more, for example.

The porous hydrogel structure has a micro-sized pore diameter or / and a high porosity within the above range, and thus may have a large surface area compared to non-porous beads. As a result, the exposure area of the harmful gas present in the case of food decay is wide, so that it is possible to detect the harmful gas more efficiently.

The hydrogel structure may include a bead, a fiber, a nonwoven fabric, a film, or a combination thereof. For example, the hydrogel structure may be beads or fibers. The shape of the beads may be spherical, elliptical, or rod-shaped, for example, spherical.

The beads or fibers can have a diameter of 200 μm to 3 mm, for example a diameter of 200 μm to 2 mm, for example a diameter of 200 μm to 1 mm, for example 200 μm to 900 mm It may have a diameter of µm, for example, may have a diameter of 200 µm to 800 µm, for example, it may have a diameter of 200 µm to 700 µm, for example, it may have a diameter of 200 µm to 600 µm Can, for example, may have a diameter of 200 μm to 500 μm, for example, may have a diameter of 200 μm to 400 μm. The hydrogel structure in the form of beads or fibers has a larger surface area than the film form, and thus the ability to detect harmful gases present in food can be improved.

The pH indicator dye may be selected from bromophenol blue (BPB), bromocresol purple (BCP), bromocresol green (BCG), metacresol purple (mCP), bromothymol blue (BTB), or mixtures thereof. You can. However, the pH indicator dye is not limited thereto, and any pH indicator dye usable in the art may be used.

The water content of the porous hydrogel structure may be 300% or more. The moisture content of the porous hydrogel structure may be, for example, 350% or more, for example 400% or more, for example 500% or more, for example 600% or more, for example 700% Or more, for example, 800% or more.

1 is a schematic diagram showing a mechanism capable of detecting food decay using a porous hydrogel structure (bead) for a gas sensor according to an embodiment.

Referring to FIG. 1, a porous hydrogel structure for a gas sensor (bead, 10) according to an embodiment includes a biodegradable polymer (1) and a pH indicator dye (2) therein, and at least one on the inside and the surface, respectively. It includes pores (3). The specific gas (for example, ammonia gas, 4) may be divided into positive and negative ions by reacting on the surface of the porous hydrogel structure (bead, 10) and / or an aqueous solution inside. The specific gas (for example, ammonia gas, 4) diffuses inside the porous hydrogel structure (bead, 10), and H ⁺ ions or OH ^- ions of the specific gas diffused and pH indicator dye react to convert color. Can represent

The specific gas may be an acid gas or a basic gas. The specific gas may be selected from ammonia (NH ₃ ) gas, hydrogen sulfide (H ₂ S) gas, ethylene gas, trimethylamine gas, acetic acid gas, carbon dioxide gas, or a mixed gas thereof. For example, the specific gas may be ammonia (NH ₃ ) gas.

The diffused specific gas may exhibit color conversion by reacting H ⁺ ions if it is an acidic gas or an OH ^- ion and a pH indicator dye when it is an acidic gas at 60 ppm or less. The diffused specific gas is specified within seconds within a porous hydrogel structure containing moisture even at a trace amount of, for example, 50 ppm or less, such as 30 ppm or less, such as 10 ppm. The H ⁺ ion or OH ^- ion of the gas reacts with the pH indicator dye to show color conversion, so that a specific gas can be easily and efficiently detected.

2 is a schematic diagram showing a mechanism capable of detecting food decay using a non-porous hydrogel structure (bead) for a gas sensor according to an embodiment to be compared.

Referring to FIG. 2, the non-porous hydrogel structure (bead) for a gas sensor according to one embodiment to be compared includes a biodegradable polymer (1) and a pH indicator dye (2) therein and has no pores inside or on the surface. It is a non-porous structure. A specific gas (for example, ammonia gas, 4) may exhibit color conversion by reacting with a specific gas (for example, ammonia gas, 4) only on the surface of the porous hydrogel structure (bead, 10).

The porous hydrogel structure for a gas sensor according to an embodiment (bead, 10) is more efficient because the exposure area for a specific gas is wide compared to the non-porous hydrogel structure for a gas sensor (bead) according to a comparative embodiment It is possible to detect a specific gas.

The porous hydrogel structure may be included therein in the form of a patch or a food storage container having high permeability in the form of a patch on the surface of the food storage packaging or food storage container. Therefore, the porous hydrogel structure can be miniaturized and portable.

The gas sensor according to another embodiment may include the aforementioned porous hydrogel structure.

According to another embodiment of the present invention, a method of manufacturing a porous hydrogel structure for a gas sensor comprises mixing a first basic aqueous solution and a biodegradable polymer solution in which a pH indicator dye is dispersed to form a first mixed solution of heterogeneous primary phase separation. Manufacturing; Adding a second emulsifier aqueous solution to the first mixed solution to prepare a second mixed solution in which second heterogeneous phase separation is performed; Removing the solvent from the second mixture to obtain a porous hydrogel structure having pores therein; And impregnating the obtained porous hydrogel structure with a second basic solution to prepare a porous hydrogel structure for a gas sensor as described above having pores on the surface.

3 is a schematic diagram of a method of manufacturing a porous hydrogel structure (bead) according to one embodiment. Referring to FIG. 3, the porous hydrogel structure (bead) according to one embodiment may be manufactured by the following method.

First, the first basic aqueous solution and the biodegradable polymer solution in which the pH indicator dye is dispersed are mixed to prepare a first mixed solution in which heterogeneous primary phase separation is performed.

The first basic aqueous solution may include NH ₄ HCO ₃ . The concentration of the first basic aqueous solution may include 1% to 20% by weight, for example, 5% to 20% by weight. If the concentration of the first basic aqueous solution is within the above range, the final result, the porous hydrogel structure for a gas sensor may have a high water content of about 300% or more. The type of the pH-indicating dye is the same as described above, so the description below is omitted.

The first phase separation of the heterogeneous phase in the first mixture may be phase separation by forming an interface between an oil phase and water. The volume ratio between the oil phase and the water is the concentration of the biodegradable polymer solution, the concentration of the basic compound aqueous solution, and / or the stirring speed of a homogenizer such as a homogenizer for preparing the first mixed solution. You can adjust it accordingly.

Next, an aqueous solution of an emulsifier is added to the first mixed solution to prepare a second mixed solution in which the second phase separation of the heterogeneous phase is achieved.

The emulsifier may be, for example, polyvinyl alcohol (PVA). However, it is not limited thereto, and any emulsifier usable in the art may be used. Separation of the second phase of the heterogeneous phase from the second mixture may be separated into three phases: an aqueous phase, an oil phase, and an aqueous phase.

Next, the solvent is removed from the second mixture to obtain a porous hydrogel structure having pores 13 therein. The step of obtaining the porous hydrogel structure may include a process of removing the solvent from the second mixed solution and simultaneously generating a gas by hydrolysis in an aqueous basic compound solution. After removing the solvent from the second mixed solution may include a step of drying. Drying in the second mixed solution may be lyophilization. The lyophilization can be performed, for example, within a temperature range of -60 ° C to 60 ° C for 30 minutes to 24 hours. The porous hydrogel structure may include a biodegradable polymer 11 and a pH indicator dye 12 therein and may have pores 13.

Next, the obtained porous hydrogel structure is impregnated with a second basic solution to prepare a porous hydrogel structure for a gas sensor described above having pores on its surface. The second basic solution may be selected from NaOH, KOH, or a combination thereof, for example, NaOH. The second basic solution may partially hydrolyze the biodegradable polymer inside the obtained porous hydro structure to have pores on the surface of the structure.

The method of manufacturing the porous hydrogel structure for the gas sensor can be mass-produced at low cost.

Hereinafter, examples of the present invention will be described. However, the following examples are only examples of the present invention, and the present invention is not limited to the following examples.

[Example]

Example  1: porosity Hydrogel Bead  Produce

A 5% by weight aqueous ammonium bicarbonate solution in which ammonium bicarbonate (NH ₄ HCO ₃ ) was dispersed in a 2 mL aqueous solution was prepared. Bromothymol as 240 mL of poly (lactide-co-glycolide) (PLGA) biodegradable polymer (manufactured by Sigma Aldrich, Mw: 30,000 to 60,000) and pH indicator dye in 7 mL of methylene chloride (CH ₂ Cl ₂ ) A biodegradable polymer solution in which blue (BTB) was dispersed at a concentration of 4 mM was prepared.

The aqueous ammonium bicarbonate solution and the biodegradable polymer solution in which the bromothymol blue (BTB) is dispersed are stirred at a rate of 12,000 rpm using a homogenizer (T25D, manufactured by IKA) to obtain a water phase and an oil phase. ) To prepare a first mixed solution in which the heterogeneous primary phase separation was performed.

To the first mixture, 150 mL of 0.1 wt% polyvinyl alcohol (PVA) emulsifier aqueous solution is added and stirred to separate the second phase of the water phase, oil phase, and water phase. A second mixed solution was prepared.

CH ₂ Cl ₂ in the second mixture The solvent was removed by evaporation and freeze-dried to obtain a porous hydrogel structure having pores therein. The obtained porous hydrogel structure was impregnated with a 0.2 M NaOH solution to prepare a porous hydrogel structure for a gas sensor having pores on its surface.

Example  2: porosity Hydrogel Bead  Produce

5% by weight of ammonium bicarbonate (NH ₄ HCO ₃₎ producing a porous hydrogel structure for a gas sensor, and the same procedures as in Example 1, except that instead of using the ammonium bicarbonate (NH ₄ HCO ₃₎ an aqueous solution of 10% by weight aqueous solution Did.

Example  3: porosity Hydrogel Bead  Produce

5% by weight of ammonium bicarbonate (NH ₄ HCO ₃₎ in Example 1, and producing the hydrogel structure for porous biosensor in the same manner except that instead of using the ammonium bicarbonate (NH ₄ HCO ₃₎ an aqueous solution of 20% by weight aqueous solution Did.

Comparative example  One: Non-porous Hydrogel Bead  Produce

Bromothymol as 240 mL of poly (lactide-co-glycolide) (PLGA) biodegradable polymer (manufactured by Sigma Aldrich, Mw: 30,000 to 60,000) and pH indicator dye in 7 mL of methylene chloride (CH ₂ Cl ₂ ) A biodegradable polymer solution in which blue (BTB) was dispersed at a concentration of 4 mM was prepared.

To the biodegradable polymer solution, 150 mL of 0.1 wt% polyvinyl alcohol (PVA) emulsifier aqueous solution was added and stirred to prepare a mixed solution in which phase separation of the water phase and the oil phase was heterogeneous.

CH ₂ Cl ₂ in the mixed solution The solvent was removed by evaporation and dried at room temperature for 4 hours to prepare a non-porous hydrogel structure for a gas sensor.

Analysis example  1: Scanning electron microscope (SEM) photo analysis

The porous hydrogel beads prepared in Example 1 and the non-porous hydrogel beads prepared in Comparative Example 1 were observed using a scanning electron microscope (JSM-7610F, manufactured by JOEL). The results are shown in FIGS. 4 and 5, respectively.

4 and 5, compared to the non-porous hydrogel beads prepared by Comparative Example 1, the porous hydrogel beads prepared by Example 1 confirm that a plurality of pores are formed on the surface and inside You can.

In addition, it can be seen that the porous hydrogel beads prepared in Example 1 had a larger pore size on the surface of the beads than the pore size inside the beads. This is because the pores inside the beads were formed due to the generation of NH ₃ and CO ₂ gases produced by ammonium bicarbonate (NH ₄ HCO ₃ ), and the pores on the surface of the beads were formed by impregnation with NaOH solution.

Analysis example  2: Water content analysis

The moisture content was analyzed for the porous hydrogel beads prepared by Examples 1 to 3. Here, the water content was fixed in the equilibrium state (in distilled water) and the swelling time of the hydrogel beads was 8 hours, and was calculated using Equation 1 below. The results are shown in FIG. 6.

[Equation 1]

Moisture content (%) = [(mass of swelled beads-mass of dried beads) / (mass of dried beads) X 100]

Referring to Figure 6, the porous hydrogel beads prepared by Examples 1 to 3 showed a water content of about 350% to about 900%, respectively.

Evaluation example  1: Gas detection evaluation

The porous hydrogel beads prepared in Example 2 were exposed to 0 ppm, 10 ppm, 30 ppm, and 60 ppm of ammonia gas, respectively, and the color change of the beads was then measured using a camera (Nikon, VH-310G2). It was observed. The results are shown in FIG. 7.

7, it can be seen that even if the porous hydrogel beads prepared in Example 3 are exposed to ammonia gas of 60 ppm or less, the pH of the interior changes gradually from yellow to blue as the pH changes to 7.6 or more. In addition, the sensitivity of the ammonia gas increased as the concentration of the ammonia gas increased.

1, 1 ', 11: biodegradable polymer, 2, 2', 12: pH indicator dye,
3, 3 ', 13: pore, 4: ammonia gas
10: porous hydrogel structure for gas sensors,
10 ': Hydrogel structure for gas sensor

Claims (22)

Biodegradable polymers; And
pH indicator dye; containing,
The porous hydrogel structure has at least one pore on the inside and the surface of the structure,
The pore size of the surface of the structure is larger than the pore size inside the structure,
The porous hydrogel structure is a porous hydrogel structure for a gas sensor in which a specific gas is diffused therein and the diffused specific gas reacts with H ⁺ ions or OH ^- ions and a pH indicator dye at 60 ppm or less to exhibit color conversion. According to claim 1,
The porous hydrogel structure is a porous hydrogel structure for a gas sensor further comprising a water layer on its surface. delete According to claim 1,
The pores on the surface of the structure are porous hydrogel structures for gas sensors, which are the result of partially hydrolyzing a biodegradable polymer. According to claim 1,
The biodegradable polymer is a porous hydrogel structure for a gas sensor comprising at least one selected from polyester polymers, anhydrides thereof, and copolymers thereof. According to claim 1,
The biodegradable polymer is a porous hydrogel structure for a gas sensor comprising a polymer represented by Formula 1 below:
[Formula 1]

In Chemical Formula 1,
R ₁ , R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, a substituted or unsubstituted C1 to C10 alkyl group, or a combination thereof;
m and n are integers of 5 to 100,000, respectively. According to claim 1,
The pores are porous hydrogel structures for gas sensors having a diameter of 1 μm to 50 μm. According to claim 1,
The porous hydrogel structure is a porous hydrogel structure for a gas sensor having a porosity of 80% or more. According to claim 1,
The porous hydrogel structure is a bead (bead), fibers, non-woven fabric, film, or a porous hydrogel structure for a gas sensor comprising a combination of these. The method of claim 9,
The beads or fibers are porous hydrogel structures for gas sensors having a diameter of 200 μm to 3 mm. According to claim 1,
The pH indicator dye is a gas selected from bromophenol blue (BPB), bromocresol purple (BCP), bromocresol green (BCG), metacresol purple (mCP), bromothymol blue (BTB), or mixtures thereof. Porous hydrogel structure for sensors. According to claim 1,
Porous hydrogel structure for a gas sensor having a moisture content of 300% or more of the porous hydrogel structure. delete According to claim 1,
The specific gas is ammonia (NH ₃ ) gas, hydrogen sulfide (H ₂ S) gas, ethylene gas, trimethylamine gas, acetic acid gas, carbon dioxide gas, or a porous hydrogel structure for a gas sensor selected from these mixed gases. delete A gas sensor comprising the porous hydrogel structure according to any one of claims 1, 2, 4 to 12, and 14. Mixing a first basic aqueous solution and a biodegradable polymer solution in which a pH indicator dye is dispersed to prepare a first mixed solution having heterogeneous primary phase separation;
Adding a second emulsifier aqueous solution to the first mixed solution to prepare a second mixed solution in which second heterogeneous phase separation is performed;
Removing the solvent from the second mixture to obtain a porous hydrogel structure having pores therein; And
A gas sensor according to any one of claims 1, 2, 4 to 12, and 14 having pores on its surface by impregnating the obtained porous hydrogel structure with a second basic solution. Method of manufacturing a porous hydrogel structure for a gas sensor comprising a; manufacturing a porous hydrogel structure. The method of claim 17,
The first basic aqueous solution is a method for producing a porous hydrogel structure for a gas sensor containing NH ₄ HCO ₃ . The method of claim 17,
Method of manufacturing a porous hydrogel structure for a gas sensor having a concentration of the first basic aqueous solution of 5% to 20% by weight. The method of claim 17,
A method of manufacturing a porous hydrogel structure for a gas sensor, in which the first phase separation of the heterogeneous phase in the first mixture is separated by formation of an interface between an oil phase and a water phase. The method of claim 17,
Method for producing a porous hydrogel structure for a gas sensor, wherein the separation of the second phase of the heterogeneous phase from the second mixture is divided into three phases: an aqueous phase, an oil phase, and an aqueous phase. The method of claim 17,
The second basic solution is a method of manufacturing a porous hydrogel structure for a gas sensor selected from NaOH, KOH, or a combination thereof.

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